Facts
Did you know that....
Ticks can be active all year round
It is generally assumed that ticks are most active between October and November and again during April and May, but studies have proved that ticks can be found questing all year round, and at temperatures as low as 3.5°C.
In the study "Age structure of a population of Ixodes ricinus (Acari: Ixodidae) in relation to its seasonal questing", Dr. A.R. Walker of the Royal Veterinary Studies, University of Edinburgh, writes:
"Two annual cohorts of both nymphs and adults were found. For both instars one cohort became apparent in early spring and the other in autumn. The timing of the cohorts of nymphs corresponded to peaks of numbers questing, but neither females nor males had any clear seasonal pattern of questing. The maximum life of questing nymphs and adults was three to four months. Nymphs and adults were found questing at all months of the year and at temperatures ranging from 3.5°C. to 29.3°C."
The seasonal activity and distribution of ticks has been linked to Schizophrenia and Multiple Sclerosis
In the International Journal of Health Geographics Dec 2002, and in research published in 2005 (Med Hypotheses, 2005;64(3):438-48), Dr. Markus Fritzsche highlighted that, globally, during the seasonal periods when Ixodid ticks are abundant, there was a significant increase in the number of babies born, who later went on to develop sporadic schizophrenia and multiple sclerosis.
"The prevalence of MS and schizophrenic birth excesses entirely spares the tropical belt where human treponematoses are endemic, whereas in more temperate climates infection rates of Borrelia garinii in ticks collected from seabirds match the global geographic distribution of MS. If the seasonal fluctuations of Lyme borreliosis in Europe are taken into account, the birth excesses of MS and those of schizophrenia are nine months apart, reflecting the activity of Ixodes ricinus at the time of embryonic implantation and birth. In America, this nine months' shift between MS and schizophrenia births is also reflected by the periodicity of Ixodes scapularis along the East Coast. With respect to Ixodid tick activity, amongst the neuropsychiatric birth excesses only amyotrophic lateral sclerosis (ALS) shows a similar seasonal trend."
In the United Kingdom humans are most likely to be bitten by Ixodes ricinus
Ixodes ricinus is a hard-bodied tick, most commonly called a 'Sheep tick'. It feeds on many different sizes of hosts, from small birds, rodents, and reptiles, to medium and large mammals (including humans).
Ticks are designed to bite and feed un-noticed
Tick saliva contains various bio-chemicals that act as anaesthetics (which numb the bite area), anti-inflammatories (which prevent swelling), anticoagulants (which stop the blood from clotting), and cement to hold the tick firmly in place. They can feed for up to seven days without causing irritation. The barbs on the tick's hypostome also keep the tick anchored in place while it feeds. It is during the introduction of saliva, and any regurgitation that may occur during the feeding, that infectious organisms can enter the body of the host, causing disease.
Ticks have evolved to allow Borrelia bacteria to live inside them
Research has revealed that ticks have special receptors in their intestines. Borrelia burgdorferi (the bacteria that cause Borreliosis / Lyme disease) express a protein which allows them to attach to the receptor. This then enables the bacteria to remain safe in the gut after they are ingested by the tick, even through the tick's moults. When the tick next takes a blood meal, another protein is expressed which enables the bacteria to detach from the receptor, and migrate to the salivary glands, where they can be injected into a host. As saliva is introduced by the tick to act as an anaesthetic, anticoagulant, and cement to anchor the tick, infection can be passed on during the biting and feeding process.
Borrelia bacteria have a cloaking device
Studies have shown that Borrelia burgdorferi activates a gene in the tick, boosting production of an immunosuppressive salivary protein. The bacteria coat themselves in this protein and, as the tick bites, they enter the skin. The protein allows them to remain invisible to the host's immune system by suppressing the immune cells. They can therefore multiply and spread through the body. Borrelia can also change form, and be present in more than one form at a time, hiding deep within tissues, and where blood circulation is poor. It is because of these abilities that Borrelia is termed a 'stealth pathogen'.
Disease transmission can occur in less than 24 hours after a tick attaches
Recent studies by the Faculty of Biological Sciences, University of South Bohemia and Institute of Parasitology, provide direct evidence that tick saliva accelerates the proliferation of Borrelia bacteria. This evidence negates previous advice that a tick needs to be attached for over 24 hours for disease transmission to occur.
Some infective organisms can be transferred from a mother tick to her offspring via the egg
Some species of tick are able to transmit certain pathogens to their offspring through the egg (transovarial transmission), and from the larval to the nymphal stage, or the nymphal to the adult stage (trans-stadial transmission).
To learn all about ticks, how they transmit diseases,
and to see them close up, CLICK THE TICK.
Tick-borne disease can affect sheep within the UK
Figures reported by the Health & Safety Laboratory indicate that up to 300,000 lambs each year are affected by tick-borne diseases, such as Louping-ill, Tick Pyaemia, and Tick-borne Fever (ADA 1992). As well as causing illness in sheep, Louping-ill, which is a Flavivirus, can also affect other large and medium-sized mammals, such as cattle, goats, horses, pigs, dogs, and deer, as well as small mammals, including shrews, wood mice, voles and hares. This virus can also affect birds, such as red grouse and ptarmigan. The first case of human Louping-ill was discovered in 1934. In humans it can present as a flu-like illness, as encephalitis, as a poliomyelitis-like illness, and a haemorrhagic fever.
Tick bites can lead to Hydrocephalus
Hydrocephalus (an accumulation of cerebrospinal fluid within the skull) is a condition which can prove to be fatal in humans. Hydrocephalus can result when either too much cerebrospinal fluid is produced, or when it is prevented from circulating or being reabsorbed. The accumulation causes rapid pressure inside the brain.
Many tick-borne diseases are able to infect both humans and animals
Babesia, a protozoal infection, has differing strains. It can cause anaemia and in some instances fatalities, particularly in splenectomised humans and animals. Anaplasma phagocytophilum is responsible for Anaplasmosis in horses, which can cause symptoms of fever, lethargy, swollen legs, low blood counts (white cells, red cells and platelets), localised haemorrhages in the skin, and abnormal coordination. Ehrlichia ovina occurs in sheep and Redwater fever in cattle. Human Granulocytic Ehrlichiosis (HGE) has emerged as an important human health concern since 1990. There are currently four ehrlichial species known to cause disease in humans.
Ticks can affect domestic animals that travel with their owners
Since the introduction of the Pet Travel Scheme (PETS) by the Ministry of Agriculture, Food and Fisheries, MAFF (now the Department for Environment, Food and Rural Affairs, DEFRA), on 28th February 2000, some 59,000 cats and dogs had entered the United Kingdom from mainland Europe by June 2002 (DEFRA 2002). The Pets Travel Scheme stipulates that the owners and veterinarians responsible for such travelling companions must also ensure suitable treatment against tapeworms and ticks before entering or re-entering the UK from abroad. Despite these regulations however, British pets travelling in Europe are at risk of exposure to several vector-borne parasitic diseases, currently termed as exotic to this country, but endemic in many parts of Europe; amongst those listed are Babesiosis and Ehrlichiosis. Having returned to the UK, a pet carrying such diseases can then infect any UK tick that happens to feed on them. The tick, in turn, can then infect the surrounding wildlife, domestic stock, and pets.
Tests for Lyme disease can be unreliable
There are several different types of test that can be performed but according to The Centres for Disease Control and prevention in the US, "there is no reliable test for Lyme disease at this time". Diagnosis must be made by clinical methods. The likelihood of a bite must be taken into account but even if a patient does not recall a bite, rash, or seeing a tick, this disease should still be given serious consideration. The gold standard of testing is recognised to be the successful culturing of the bacterial infection. However, this form of testing is not available in the UK.
The annual financial and personal cost of Lyme disease can be great
In a study performed by staff of the Microbiology Dept, Raigmore Hospital, Inverness, it was estimated that the likely annual cost due to Lyme disease could be in the region of £331,000 and up to £615,000. This was based on the review of some 2,110 samples sent from laboratories serving 59% of the Scottish population, and of which 326 were positive. The study also goes on to question whether there is sufficient focus on prevention and the best management of this disease. Prior to correctly being diagnosed as suffering from a Borreliosis / Lyme disease infection, many patients are given a multitude of incorrect diagnoses: Carpal tunnel syndrome, Rheumatoid Arthritis, Temporal Mandibular Disorder, Migraine, Viral Meningitis, Multiple Sclerosis, Motor Neuron disease, Chronic Fatigue Syndrome, Myalgic Encephalitis, atypical migraine, Parkinson's Disease, ADHD and various psychological disorders for example. Such financial and personal implications to the patient, and any relatives/dependants, should also be considered.
